β′ and βprecipitation in an Al-Mg alloy studied by DSC and TEM

被引：136

作者：

Starink, MJ ^{[1
]}

Zahra, AM ^{[1
]}

机构：

[1] CNRS, Ctr Thermodynam & Microcalorimetrie, F-13331 Marseille 3, France

来源：

ACTA MATERIALIA | 1998年 / 46卷 / 10期

关键词：

D O I：

10.1016/S1359-6454(98)00053-6

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Precipitation in Al-16 at.%Mg is investigated by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The shape of the beta' formation DSC effect is interpreted with a novel theory and the curves obtained on the basis of this new theory it well to the experimental curves. The s parameter derived from these fits, which is akin to the Avrami parameter n appearing in the Johnson-Mehl-Avrami-Kolmogorov model, is larger than 2.5, indicating that beta' precipitation is an autocatalytic process. TEM showed the abundant presence of defects (mostly dislocation loops) but no evidence of nucleation of beta' precipitates on these defects. The enthalpies of formation of the beta and beta' phases are derived as 15.7 and 11.5 kJ per mol Mg, respectively. (C) 1998 Acta Metallurgica Inc.

引用

页码：3381 / 3397

页数：17

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